XPost: linux.debian.bugs.dist, linux.kernel 
 From: axboe@kernel.dk 
  
 On 10/13/25 11:47 AM, Salvatore Bonaccorso wrote: 
 > Hi Jens, 
 > 
 > Kevin Lumik reported in Debian the following issue (not exactly a 
 > minimal reproducer, but bisection results follows): 
 > 
 > On Fri, Sep 26, 2025 at 10:34:22AM +0300, Kevin Lumik wrote: 
 > 
 >> Dear Maintainer, 
 >> 
 >> After upgrading from Debian Bookworm to Trixie, an issue within KVM guests 
 when creating an LVM snapshot of its volume 
 >> has surfaced. When a LVM snapshot is taken from the host, the guest starts 
 to get I/O errors. The issue seems to only 
 >> appear when aio=io_uring is specified in the KVM drive parameters and also 
 seems to resolve when downgrading the kernel 
 >> package down to 6.1. The issue is also not reproducible when using 
 aio=native. 
 >> 
 >> KVM args for the drive: "-drive id=drive- 
 >> virtio0,format=raw,file=/dev/dom/vps_testsql,cache=none,aio=i 
 _uring,index=0,media=disk,if=virtio" 
 >> 
 >> An IO workload is being created in the VM using "fio --randrepeat=1 
 --ioengine=io_uring --direct=1 --gtod_reduce=1 -- 
 >> name=randwrite --filename=/root/test.bin --bs=4k --iodepth=64 --runtime=60 
 --numjobs=32 --readwrite=randwrite --size=1G 
 >> --rwmixread=75 --group_reporting" 
 >> 
 >> After running "lvcreate -s /dev/dom/vps_testsql -n test -L 1G" on the host 
 we can observe fio erroring out: 
 >> 
 >> ... 
 >> fio: io_u error on file /root/test.bin: Input/output error: write 
 offset=46977024, buflen=4096 
 >> fio: pid=7367, err=5/file:io_u.c:1876, func=io_u error, error=Input/output 
 error 
 >> fio: io_u error on file /root/test.bin: Input/output error: write 
 offset=261505024, buflen=4096 
 >> fio: pid=7374, err=5/file:io_u.c:1876, func=io_u error, error=Input/output 
 error 
 >> fio: io_u error on file /root/test.bin: Input/output error: write 
 offset=973840384, buflen=4096 
 >> fio: io_u error on file /root/test.bin: Input/output error: write 
 offset=9637888, buflen=4096 
 >> fio: io_u error on file /root/test.bin: Input/output error: write 
 offset=159965184, buflen=4096 
 >> fio: io_u error on file /root/test.bin: Input/output error: write 
 offset=857505792, buflen=4096 
 >> fio: io_u error on file /root/test.bin: Input/output error: write 
 offset=90787840, buflen=4096 
 >> fio: io_u error on file /root/test.bin: Input/output error: write 
 offset=26427392, buflen=4096 
 >> fio: io_u error on file /root/test.bin: Input/output error: write 
 offset=955621376, buflen=4096 
 >> fio: io_u error on file /root/test.bin: Input/output error: write 
 offset=96169984, buflen=4096 
 >> fio: pid=7372, err=5/file:io_u.c:1876, func=io_u error, error=Input/output 
 error 
 >> fio: pid=7362, err=5/file:io_u.c:1876, func=io_u error, error=Input/output 
 error 
 >> fio: io_u error on file /root/test.bin: Input/output error: write 
 offset=203702272, buflen=4096 
 >> fio: io_u error on file /root/test.bin: Input/output error: write 
 offset=814649344, buflen=4096 
 >> fio: io_u error on file /root/test.bin: Input/output error: write 
 offset=91467776, buflen=4096 
 >> fio: io_u error on file /root/test.bin: Input/output error: write 
 offset=948256768, buflen=4096 
 >> fio: io_u error on file /root/test.bin: Input/output error: write 
 offset=105295872, buflen=4096 
 >> fio: io_u error on file /root/test.bin: Input/output error: write 
 offset=75247616, buflen=4096 
 >> fio: io_u error on file /root/test.bin: Input/output error: write 
 offset=1062293504, buflen=4096 
 >> fio: io_u error on file /root/test.bin: Input/output error: write 
 offset=111955968, buflen=4096 
 >> fio: io_u error on file /root/test.bin: Input/output error: write 
 offset=942563328, buflen=4096 
 >> fio: io_u error on file /root/test.bin: Input/output error: write 
 offset=117354496, buflen=4096 
 >> fio: io_u error on file /root/test.bin: Input/output error: write 
 offset=1050402816, buflen=4096 
 >> fio: io_u error on file /root/test.bin: Input/output error: write 
 offset=125419520, buflen=4096 
 >> fio: io_u error on file /root/test.bin: Input/output error: write 
 offset=129044480, buflen=4096 
 >> fio: pid=7369, err=5/file:io_u.c:1876, func=io_u error, error=Input/output 
 error 
 >> fio: pid=7373, err=5/file:io_u.c:1876, func=io_u error, error=Input/output 
 error 
 >> fio: pid=7348, err=5/file:io_u.c:1876, func=io_u error, error=Input/output 
 error 
 >> fio: pid=7375, err=5/file:io_u.c:1876, func=io_u error, error=Input/output 
 error 
 >> fio: pid=7358, err=5/file:io_u.c:1876, func=io_u error, error=Input/output 
 error 
 >> fio: pid=7359, err=5/file:io_u.c:1876, func=io_u error, error=Input/output 
 error 
 >> 
 >> randwrite: (groupid=0, jobs=32): err= 5 (file:io_u.c:1876, func=io_u 
 error, 
 error=Input/output error): pid=7344: Thu Sep 
 >> 25 16:28:30 2025 
 >>   write: IOPS=194k, BW=758MiB/s (795MB/s)(3976MiB/5244msec); 0 zone resets 
  
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